1. Field of the Invention
The present invention relates to a buckle for a seat belt provided mainly in vehicles, and more particularly, to a seat belt buckle whose release push-button faces toward the passenger when mounted.
2. Description of the Prior Art
Vehicles are now equipped with a seat belt for protection of the passenger in case of emergency, for example, against collision, and various seat belt buckles have heretofore been proposed. For example, there have been proposed the so-called push-button type buckles such as those disclosed in U.S. Pat. No. 4,027,362 (except for the third and fourth embodiments illustrated in FIGS. 6 to 8) wherein a push-button movable perpendicularly to the direction of insertion of a tongue is attached to the buckle body and by operating the push-button the tongue is released from the buckle body, and the so-called slide-button type buckles such as those disclosed in U.S. Pat. No. 4,136,425 and U.S. Pat. No. 4,027,362 (only the fourth embodiment shown in FIG. 8) wherein a push-button slidable in parallel with the direction of insertion of a tongue is attached to the buckle body and by operating the slidable push-button the tongue is released from the buckle body.
However, such conventional buckles do not appear to have been constructed by taking into consideration their operationality under actual use conditions, in other words, by ignoring to a certain extent that they would be attached to a vehicle because designers were perhaps concerned too much with an improvement in performance of the buckles. That is, a buckle is usually mounted on the inner side of the lap belt (adjacent to to longitudinal center line of a vehicle), but in a push-button type buckle when mounted, the push-button operating surface faces toward the console box side, therefore it is difficult to operate the push-button for releasing the tongue from the buckle body. U.S. Pat. Nos. 3,851,360; 3,871,090 and 4,027,362 (only the third embodiment depicted in FIGS. 6 and 7) disclose each a seat belt buckle having a push-button which, when mounted, faces toward the passenger. However, many slide-button or push-button type buckles still leave room for improvement; that is, the operationality of the push-button may be good, but since the push-button is exposed, the tongue may be accidentally released when an elbow or other part of the passenger happens to touch the puch-button operating surface. In many cases, a tongue is locked by a latch member only at a portion, which is generally formed into a notch or recess along one longitudinal side of the tongue. It is thusnecessary to make the tongue rather thick in order to impart sufficient durability to the tongue, resulting in a weight increase. In some instances, for example, in the buckle illustrated in FIGS. 6 and 7 of U.S. Pat. No. 4,027,362, a releasing force is not experted perpendicularly onto the latch member from the release push-button, thereby making the release of the latch member from its corresponding tongue difficult.